Brother Oswin, the novice and Cadfael's apprentice, has a much larger role in the television series than in the books. In the books he does not appear until the middle of the series. He largely takes the place of Brother Mark, who left the Abbey to run the leper house at St. Giles. Mark can be seen in "The Leper of St. Giles". In "The Virgin in The Ice" Brother Elyas was the brother accused of the rape and murder of Sister Hilaria, not Oswin.